It's Not Rocket Science

If you can't find an AN fitting for your application, find a local hydraulic shop and use simple SAE fittings. They may not be red or blue, buy they'll fit just fine.

"AN" (Army-Navy) sizes were established by the Aerospace industry years ago. The numbers are equal to the outside diameter [OD] of the tubing in 1/16". Since tubing and hoses can have different wall thicknesses, the size number does not necessarily tell you how large the inside diameter will be.

Each AN size number has its own standard thread size [see column three of the chart]. These are the same thread sizes that have been used in aircraft and industrial applications for many years. For some odd reason, the automotive industry wants to make AN fittings sound like something special.

AN Size	Metal Tube O.D.	Thread Size
2	1/8"	5/16-24 SAE
3	3/16"	3/8-24 SAE
4	1/4"	7/16-20 SAE
5	5/16"	1/2-20 SAE
6	3/8"	9/16-18 SAE
8	1/2"	3/4-16 SAE
10	5/8"	7/8-14 SAE
12	3/4"	1-1/16-12 SAE
16	1"	1-5/16-12 SAE
20	1-1/4"	1-5/8-12 SAE
24	1-1/2"	1-7/8-12 SAE
28	1-3/4"	2-1/4-12 SAE
32	2"	2-1/2-12 SAE

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